Disposable absorbent articles, such as diapers, are often constructed with an absorbent core assembly adapted to absorb bodily exudates and positioned between layers of materials. Such absorbent core assemblies may include a mixture of fibrous and particulate materials (e.g., fluff material and superabsorbent polymer), which are formed into a batt or wad. In turn, the batt or wad may be positioned between two or more layers of materials. One such layer may be a dusting layer adapted to face the wearer's body. Another such layer may be a core wrap adapted to face away from the person's body. The batt may not extend the entire length of the diaper, and thus, is generally intended to extend longitudinally inboard of the end edges of the diaper.
In the manufacturing of the absorbent core assemblies, a variety of batt forming techniques may be utilized. For example, discrete batts may be formed with the use of vacuum zones within a laydown drum. In some configurations, superabsorbent polymer and fluff material are deposited onto a web partially wrapped around the outer surface of the laydown drum. Vacuum zones on the outer surface of the laydown drum help place and hold the superabsorbent polymer and fluff material in desired locations on the web. However, using some current techniques and apparatuses, some superabsorbent polymer and fluff material may be inadvertently deposited outside of the vacuum zones and outside desired locations on the web. For example, in some instances, superabsorbent polymer may be deposited substantially along the entire length of the diaper. As a result, the superabsorbent polymer may subsequently migrate through the topsheet, causing the superabsorbent polymer to be deposited on the wearer's skin. Such deposits may cause skin irritation; may be believed to cause skin irritation; and/or may be aesthetically unacceptable to a consumer. Additionally, fluff material inadvertently deposited substantially along the entire length of the diaper may interfere with an end seal necessary to contain the absorbent core assembly.
In response to the aforementioned problems, some laydown drums may be configured with additional systems to help prevent the superabsorbent polymer and fluff mate from migrating outside the vacuum zones. For example, some laydown drums may include pneumatic systems that force compressed air through zones in the laydown drum to help prevent the deposit of particulate material along the entire length of the diaper. However, such systems add cost and complexity to the manufacturing process.
Thus, there remains a need for simplified methods and apparatuses for forming batts comprising particulate material (e.g., fluff material and superabsorbent polymer) for use as a component in an absorbent core assembly.